A conventional disc brake rotor of a motor vehicle typically includes two vertically parallel brake discs which are maintained in their parallel orientation by a plurality of radially extending ribs positioned between and connecting opposing surfaces of the brake discs. A conventional rotor also includes a vertical hub which at its outer edge has a horizontally oriented "closed" support structure that extends to the nearest brake disc, is joined to the same at its inner horizontal edge, and thereby supports the brake discs. The conventional rotor hub is provided with a number of equally spaced holes (typically four or five) that are arranged in a circular pattern and permit the brake rotor to be mounted to a rotatable axle flange via stud bolts and lug nuts. The brake rotor acts with brake calipers containing brake pads which are applied to the brake discs to stop rotation of a vehicle wheel which typically is also mounted to the axle flange on the outboard side of the brake rotor. When the brake calipers are activated and cause the brake pads to contact the brake discs, frictional thermal energy is produced and the brake discs as well as the other portions of the brake rotor become hot through absorption of some of the thermal energy.
Because the support structure of a conventional brake rotor is situated to just one side (normally the outboard side) of the two brake discs, air is blocked from flowing to the flange side of the brake rotor and cooling of the brake discs is prevented.